Apparatus for grinding glass slides or the like

ABSTRACT

A grinding apparatus designed to grind articles such as glass slides. A work carriage is situated over a pair of guide bars and supported for free movement therealong by way of a bearing means operatively connected with the work carriage and having rolling contact with the guide bars. A rotary grinding unit is supported in a floating manner with respect to a frame of the apparatus so that the rotary grinding unit can, if necessary, yield when encountering extreme grinding stresses.

[ 1 June 6, 1972 United States Patent White ...5I'/99 51/92 ....5l/92 MacGregor................................51/99 .308/6 C 1,219,038 3/1917 Philippi...

2,492,684 12/ 1949 Coates 2,624,984 l/l953 Zuzelo 3,190,703 6/1965 Thomson et m 0 S L G G mm m .m... n D m mm m arm a w wM Fm w m mw Tmhn Pmmm P L v ASmA m mm Island City, NY.

Dec. 29, 1969 Primary Examiner-William R. Armstrong Attorney-Blum, Moscovitz, Friedman & Kaplan [22] Filed:

ABSTRACT Appl. No.:

A grinding apparatus designed to grind articles such as glass slides. A work carriage is situated over a pair of guide bars and supported for free movement therealong by way of a bearing means operatively connected with the work carriage and hav- 90. WW S E 4H 4 8 V 5 a "5 Um9 5 m9 m4 "7 "H min" mmm f W d Sud i UhF 1]] 2 8 555 l[[ ing rolling contact with the guide bars. A rotary grinding unit is supported in a floating manner with respect to a frame of the apparatus so that the rotary grinding unit can, if necessary, yield when encountering extreme grinding stresses.

References Cited UNITED STATES PATENTS 1,493,787 5/1924 Little et al. 4Claims, 6Drawing Figures PATENTEUJUH 8l972 3.667.166

sum 10F INVENTOR. JAMES C. WHITE ATTORNEYS PATENTEDJUH 61972 3,667, 166

sum 30F 4 PATENTEDJUH 61872 3,667,166

SHEET w 4 JAMES C. WHl-TE ATTORNEY APPARATUS FOR GRINDING GLASS SLIDES OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to grinding apparatus.

More particularly, the present invention relates to a grinding apparatus designed to grind articles such as glass slides of the type used to carry specimens which are to be observed through a microscope, for example.

Such glass slides must be ground at their edges. A relatively large number of such slides are usually grouped together so that their edges can all be ground during operations which include several passes of the groups os slides at their edges along a rotary grinding unit such as a suitable rotary grinding stone of cylindrical configuration. For this purpose the work is mounted on a suitable carriage which can reciprocate with respect to the grinding stone. At the present time it is conventional to support such a carriage for movement along ways similar to the ways of a machine tool such as a lathe or milling machine. However, with such conventional structure extremely rapid wear of the ways is encountered because of the extremely hard grit and other foreign particles which unavoidably fall onto the ways from the grinding tool as well as from the work. Such extremely hard particles unavoidably become located at the area of sliding contact between the carriage and the ways, so that a smooth accurate guiding of the carriage cannot be maintained and serious maintenance problems are encountered. Practical experience has shown that apparatus of this type must be discarded after approximately 1 year of use. The constant reciprocation under the grinding stresses results in extremely severe wear and consequent loss of tolerance control in the grinding operations.

SUMMARY OF THE INVENTION It is accordingly a primary object of the invention to provide an apparatus which will avoid the above drawbacks.

In particular, it is an object of the invention to provide for a work carriage of the above general type a grinding structure which will have a far longer operating life than has been possible up to the present time with conventional ways as referred to above.

Moreover, it is an object of the invention to provide such a structure with the capability of maintaining the accuracy in the guiding of the work carriage over an extremely long operating life with very little if any maintenance.

It is also an object of the invention to provide a structure of the above general type which is capable of protecting the grinding tool against extreme stresses.

Thus, it is an object of the invention to provide a construction which will reliably limit the load encountered by the grinding tool so as to increase the life of the latter and reduce the maximum stresses which will .be encountered during operation of the machine, thus increasing its operating life in this way also.

According to the invention the work carriage is situated over a pair of guide bars. A bearing means, which has a purely rolling contact with the guide bars, supports the work carriage for movement therealong. Because of this rolling contact, the excessive and rapid wear resulting from the sliding contact of conventional structures is avoided and an accurate guiding of the carriage over a long operating life is assured.

In addition, a rotary grinding means is carried by a floating support means which supports the rotary grinding means for free movement with respect to the frame of the machine. In this way it is possible for the rotary grinding means to yield when extreme grinding stresses are encountered, so that in-this way also the operating life of the apparatus is increased.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a simplified, partly schematic, perspective illustration of a grinding-apparatus according to the invention;

FIG. 2 is a partly sectional side elevation of the apparatus of FIG. 1;

FIG. 3 is a fragmentary transverse elevation of the structure of FIG. 2, at a scale larger than FIG. 2, taken along line 3-3 of FIG. 2 in the direction of the arrows;

FIG. 4 is a fragmentary partly sectional and partly schematic plan view of the structure of FIG. 2, also at a scale larger than FIG. 2, taken along the line 4-4 of FIG. 2 in the direction of the arrows;

FIG. 5 is a fragmentary side elevation of a bearing unit forming part of the structure of the invention, taken along line 5-5 of FIG. 3 in the directions of the arrows and showing the structure at a scale larger than FIG. 3;

FIG. 6 is a transverse section of the structure of FIG. 5 taken along line 66 of FIG. 5 in the direction of the arrows.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, there is shown in FIG. 1 a carriage 10 for carrying the work 12. The work 12 is in the form of groups 14 of slides situated in a suitable tray 16. Thus, the slides will only have exposed upper edges which are to be ground. A clamping plate 18 is horizontally movable for pressing the work 12 against an end wall 20 of the tray 16, with this end wall 20 itself being pressed against the end wall 22 of the carriage 10. For this purpose the pressing plate 18 is acted upon by a piston of a compressed air cylinder unit 24 receiving compressed air from any suitable source capable of being controlled by the operator through a suitable valve so that after the work 12 is situated in the tray 16 it can be reliably held therein by urging the clamping plate 18 toward the end 20 of the tray 16. The unit 24 is itself fixed to the bottom wall of the carriage 10. At its rear end the carriage 10 has a handle 26 making it possible for the operator to retract the carriage to the position shown in FIG. 1 and illustrated the left of the FIG. 2 in dot-dash lines.

The illustrated apparatus also includes a frame means 28 composed of several uprights 30 interconnected by suitable transverse members 32. This frame means 28 carries the various components of the apparatus referred to below.

The left cross member 32 shown in FIG. 1 fixedly carries an elongated support beam or plate 34 fixed at one end to this member 32 so as to form a cantilever support. This support 34 terminates at its left end, as viewed in FIG. 1, in an upstanding flange 36. A pair of guide bars 38 of circular cross section, fixed at one end to the flange 36, extend longitudinally along and are spaced above the cantilever beam 34. The flange 36 is notched together with the region of the beam 34 adjacent to flange 36 so as to provide openings to accommodate a sprocket wheel 40 which is supported for free rotary movement on a pin 42 carried by the flange 36 and extending across the notch thereof as indicated in FIG. 2.

An elongated carriage-moving chain 44 extends around the sprocket 40 and is fixed at one end to a bar 46 fixed to an extending downwardly from the carriage 10. Another bar 48 is fixed to and extends downwardly from the opposite end of the carriage 10. This bar 48 is fixed to the other end of the chain 44. From the bar 48 the chain 44 extends around a second sprocket 50.

This second sprocket 50 is fixed to a rotary drive shaft 52 supported in part for rotary movement by a bearing 54 mounted on the right cross frame member 32 shown in FIG. 1. This frame member 32 is formed with bores which respectively receive the ends of the guide bars 38 opposite from the flange 36, so that in this way the guide bars 38 are supported between the flange 36 and the right cross member 32 shown in FIG. 1. This membermayitself be further supported by triangular reinforcements 56 carried by the right uprights 30 of FIG. 1. The support 32 shown at the right in FIG. 1 is also formed with a notch through which the sprocket 50 extends and through which the part of the chain 44 which extends around the sprocket 50 also extends. FIG. 4 illustrates most clearly how the shaft 52 is also supported by a second bearing 58. This shaft 52 is fixed with a component 60 of a clutch 62 which includes a movable component 64 slidably keyed to a drive shaft 66, as by being splined thereon, for example, for axial movement with respect to the drive shaft 66 while being constrained to rotate therewith. This shaft 66 is itself supported for rotary'movement by any suitable bearings situated on the cross member 32 shown on the right in FIGS. 1 and 4. This member 32 also carries a compressed air cylinder 68 having its piston operatively connected with the movable clutch component 64 in a manner shown diagrammatically in FIG. 4, so that the clutch member 64 can be displaced axially between the solid line engaged position and the dot-dash line disengaged position illustrated in FIG. 4.

The drive shaft 66 fixedly carries a sprocket 70 around which extends a chain 72 driven from a motor 74 mounted on a suitable pedestal 76 and driving a sprocket 78 which drives the chain 72.

The right bar 30 of FIG. 1 carries, through a suitable bracket, a control switch 80 situated over the chain 44 in the path of movement of the bar 48 to be engaged by the latter for a purpose referred to below.

A bearing means is provided to support the carriage for movement along the guide bars 38. This bearing means includes for each guide bar 38 a plurality of units 82 one of which is shown in detail in FIGS. 5 and 6. Each unit 82 includes an inner flat bearing plate 84 having a convex elongated peripheral edge 86 along which a plurality of concave rollers 88 are freely movable, these rollers being distributed along the peripheral edge 86 6f the bearing plate 84 in the mannershown most clearly in FIG. 5. A pair of endless chains 90 respectively support the rollers 88 between themselves for free rotary movement on suitable pins, for example, which extend between and are fixed to the pair of coextensive endless chains 90, so that in this way the distribution of the rollers 88 along the periphery 86 of the plate 84 is maintained. As was indicated above the bars 38 are of circular cross section and the concave rollers 88 have exterior surfaces which in any plane which contains the axis of the rollers forms part of a circle corresponging to that of the cross section of the bar 38 as well as to that of the cross section of the periphery 86, so that in this way a precise rolling contact is achieved between the bearing rollers 88 and the bar '38 and plate 84. The bearing means includes a bar 92 fixed .to and extending downwardly fromthe carriage lo and notched at its bottom end to receive the bearing structure in the manner shown most clearly in FIG. 6. The bar 92 fixedly carries a pin 94 which extends across the notch through the bearing plate 84 in the manner shown most clearly in FIGS. 5 and 6. The unit shown in FIGS. 5 and 6 is carried by a vertically extending bar 92 the plane of which extends in the direction of movement of the carriage 10. Thus, the unit 82 shown in FIGS. 5 and 6 is situated in a vertical plane which contains the axis of the bar 38.

However, the bearing means includes for each bar a pair of additional units 82 identical with that described above but carried in this case by a plate 96 which extends in a plane which is transverse with respect to the direction of movement of the carriage I0, as shown most clearly in FIG. 3. This plate 96 has a pair of inwardly inclined extensions 98 which are notched so as to receive the pair of inclined units 82 shown at the right in FIG. 3. These units are oppositely inclined in planes which intersect at and contain the axis of the right bar 38 shown in FIG. 3, and these units 82 coact with the bar 38 in the same way as the unit 82 described above in connection with FIGS. 5 and 6. In the illustrated examples the carriage I0 is provided at the region at one of its ends with a vertical unit 82 engaging one bar 38 and a pair of oppositely inclined units 82 engaging the other bar 38. At its other end the carriage 10 carries a pair of oppositely inclined units 82 on a supporting plate 96 but coacting with the left bar 38 of FIG. 3 while at this other end of the carriage 10 a vertical unit 82 coacts with the right bar 38 of FIG. 3. This arrangement of the vertical and inclined units 82 is particularly apparent from FIG. 4.

In order to grind the work 12, a rotary grinding means 100 is provided in the form of rotary cylindrical grinding wheels or stones the size of which is adequate to engage all of the work during a single pass thereof to the right, as viewed in FIGS. 1 and 2, beneath the rotary grinding means 100. The grinding stones 102 which form the grinding means are fixed on a rotary drive shaft 104 supported in bearings 106 and extending beyond the left bearing 106 shown in FIGS. 1 and 3 where the shaft 104 is fixed with a gear 108 driven by a timing belt 110 which in turn is driven by a pinion I12 fixed on a drive shaft 114 driven by a motor 116 supported on a bracket 1 18 which is fixed to an arm 120 of a swingable support means 122 providing a floating support means for the rotary grinding means 100.

For this latter purpose the support means 122 includes in addition to the arm 120, which carries the bracket 1 18, a parallel arm 124, the parallel arms 120 and 124 being interconnected by a transverse arm 126 carrying adjustable stop screws 128 which will engage the upper left transverse bar 32 of the frame 28 for limiting the extent of downward movement of the rotary grinding means 100. At their right free ends, as viewed in FIG. 1, the arms 120 and 124 are bored so that a rod 130 will extend freely therethrough, this rod 130 being carried by bearings 132 which are fixed to the right uprights 30 of the frame means 28, as viewed in FIG. 1. In this way the floating support means 122 is swingably connected to the frame means 28 so as to support the rotary grinding means 102 for yielding movement when it encounters extreme grinding stresses.

The upper left transverse bar 32 of FIG. I also fixedly carries an upright 134 which in turn fixedly carries a pivot pin 136 supporting a lever 138 for swinging movement. This lever is pivoted at one end to a pin 140 which is fixed to the transverse bar 126 of the floating frame means 122. The other end of the lever 138 is pivoted to the piston of a compressed air cylinder 140 which is pivotally supported on a bar 142 fixed to and extending horizontally from one of the uprights 30 in the manner shown in FIG. 1. I

The above structure operates as follows:

Initially the switch 80 is open, and in this position a solenoid valve of an unillustrated conduit through which compressed air flows acts on the compressed air cylinder 68 so as to place the clutch 62 in its disengaged position, and at this time the compressed air fed to the cylinder ,140 is also regulated through a suitable solenoid valve, when the switch 80 is open, so as to raise the floating support means 122 to the position shown in FIG. I where the rotary grinding means 100 is situated well above the upper surface of the work 12.

In this position of the parts the operator can load the carriage 10 with the work 12, actuating in a known manner the air cylinder 24 so as to clamp the work 12 in a position to be acted upon by the grinding tool 100. The drawings schematically illustrate water hoses or pipes 144 terminating in nozzles for directing cooling sprays onto the work and grinding means 100.

In order to initiate the operations the operator will close a switch in order to start the driving motor 74 which still cannot drive the shaft 52 because the clutch 62 is disengaged. The operator will grasp the handle 26 and will manually move the carriage 10 to the right from dot-dash line position shown in FIG. 2 until the leading edge of the work is situated beneath the grinding wheel 100, whereupon the operator will manually control the cylinder 140 so as to gently lower the grinding wheel 100 into engagement with the leading edge of the work.

At the same time that the motor 74 was started, the motor '1 16 was also energized so that the grinding means 100 operates continuously with the motor 74 as long as the apparatus is turned on, as through a suitable master switch. With the grinding wheel thus placed in engagement with the work, the operator will close the switch 80 so that the cylinder 68 will receive compressed air to engage the clutch 62, and now the chain 44 will be slowly driven so as to advance the work slowly toward the right, as viewed in FIG. 2, and the operations on the work by the rotary grinding means is schematically illustrated in' FIG. 2.

These operations can continue automatically until the bar 48 engages the switch 80 so as to automatically open the latter, thus terminating the feeding stroke. At the same time the compressed air will enter the lower end of the cylinder 140 to raise the floating support means 122, and now the operator can simply grasp the handle 26 so as to return the work to its starting position, after which the above operations can be repeated. The stop screws 128 are adjusted so as to determine the final stroke, and when these stop screws press against the upper cross bar 32 shown at the left of FIG. 1, it is known that the desired extent of the grinding has been achieved.

It will be noted that with this apparatus the movement of the carriage along the guide bars 38 is achieved through the bearing means described above, this bearing means including the units which are similar to Thompson bearings. Because of the exclusive rolling contact provided between the bearing means and guide bars 38, the excessive, rapid wear which formerly was encountered with sliding contact is eliminated, and the structure of the invention operates very reliably in a most accurate manner over an extremely long period of time, which in fact is far longer than would have been initially expected from the use of the bearings in the combination of the invention.

The advantages of the structure are further enhanced by the feature providing the above-described floating support means 122 for the rotary grinding means 100. In the event that the rotary grinding means 100 encounters extreme stresses, it is possible for the support assembly 122 to yield upwardly in opposition to the downwardly acting compressed air within the cylinder 140 so as to make it possible on the one hand for the rotary grinding means 100 to yield when it encounters an extremely great load while at the same time providing through the cylinder 140 a downward force which maintains the grinding means 100 in engagement with the work in a manner which will achieve the best possible grinding operations unless something unexpected is encountered to bring about the upward yielding achieved by way of the floating support means 122. Although it is preferred to use this latter feature of the invention in combination with the structure which supports the carriage 10 for movement, this latter structure as well as the floating support means 122 obviously can be used separately in other combinations.

1 claim:

1. In an apparatus for grinding slides or the like, frame means, at least a pair of parallel guide bars carried by said frame means, a work carriage located over said guide bars, bearing means operatively connected with said carriage and said bars for supporting said carriage on said bars for movement therealong, said bearing means having rolling contact with said bars, an elongated rotary grinding means situated at an elevation higher than said carriage for grinding work mounted thereon during movement of said carriage beneath said rotary grinding means, said elongated rotary grinding means having a length sufiiciently great to grind the entire work carried by said work carriage during one pass of the latter beneath said rotary grinding means, and floating support means supporting said grinding means and operatively connected with said frame means for free movement with respect thereto in a manner providing for yielding of said rotary grinding means when the latter encounters extreme grinding stresses, said floating support means including a support carry ing said rotary grinding means and having a rear end swingably connected to said frame means for free swinging movement with respect thereto, and pneumatic means for maintaining said support at a given elevation during movement of said carriage with respect to said rotary grinding means and for swinging said support upwardly to a rest position after completion of a pass of the work on said carriage beneath said rotary grinding means, and said support having a front end portion situated over a portion of said frame means, one of the latter portions carrying a stop means which is adjustable and which limits the extent of downward swinging of said support to determine the extent to which work is ground by said rotary grinding means.

2. The combination of claim 1 and wherein a moving means is operatively connected with said work carriage for moving the latter along a given work stroke, and switch means situated in the path of movement of said carriage for automatically actuating said pneumatic means to raise said support at the end of a work stroke.

3. The combination of claim 1 and wherein said adjustable stop means includes at' least one stop screw carried by said support for engaging said frame means.

4. The combination of claim 1 and wherein said bearing means is made up of a plurality of units each of which includes a roller plate, a plurality of rollers distributed along the periphery of said plate for rolling along said periphery, a pair of endless chains operatively connected with said rollers for maintaining them distributed along said periphery of said plate for free rolling movement therealong, and said rollers of each unit extending between said plate thereof and one of said bars, and having rolling engagement with the latter, said bearing means including three of said units coacting with each bar, one of said three units being situated in a substantially vertical plane which contains the axis of said bar and the other two of said three units being situated respectively in a pair of oppositely inclined planes both of which contain and intersect at the axis of said bar, the pair of oppositely inclined units which coact with one bar being transverely aligned with the vertical unit which coacts with the other bar. 

1. In an apparatus for grinding slides or the like, frame means, at least a pair of parallel guide bars carried by said frame means, a work carriage located over said guide bars, bearing means operatively connected with said carriage and said bars for supporting said carriage on said bars for movement therealong, said bearing means having rolling contact with said bars, an elongated rotary grinding means situated at an elevation higher than said carriage for grinding work mounted thereon during movement of said carriage beneath said rotary grinding means, said elongated rotary grinding means having a length sufficiently great to grind the entire work carried by said work carriage during one pass of the latter beneath said rotary grinding means, and floating support means supporting said grinding means and operatively connected with said frame means for free movement with respect thereto in a manner providing for yielding of said rotary grinding means when the latter encounters extreme grinding stresses, said floating support means including a support carrying said rotary grinding means and having a rear end swingably connected to said frame means for free swinging movement with respect thereto, and pneumatic means for maintaining said support at a given elevation during movement of said carriage with respect to said rotary grinding means and for swinging said support upwardly to a rest position after completion of a pass of the work on said carriage beneath said rotary grinding means, and said support having a front end portion situated over a portion of said frame means, one of the latter portions carrying a stop means which is adjustable and which limits the extent of downward swinging of said support to determine the extent to which work is ground by said rotary grinding means.
 2. The combination of claim 1 and wherein a moving means is operatively connected with said work carriage for moving the latter along a given work stroke, and switch means situated in the path of movement of said carriage for automatically actuating said pneumatic means to raise said support at the end of a work stroke.
 3. The combination of claim 1 and wherein said adjustable stop means includes at least one stop screw carried by said support for engaging said frame means.
 4. The combination of claim 1 and wherein said bearing means is made up of a plurality of units each of which includes a roller plate, a plurality of rollers distributed along the periphery of said plate for rolling along said periphery, a pair of endless chains operatively connected with said rollers for maintaining them distributed along said periphery of said plate for free rolling movement therealong, and said rollers of each unit extending between said plate thereof and one of said bars, and having rolling engagement with the latter, said bearing means including three of said units coacting with each bar, one of said three units being situated in a substantially vertical plane which contains the axis of said bar and the other two of said three units being situated respectively in a pair of oppositely inclined planes both of which contain and intersect at the axis of said bar, the pair of oppositely inclined units which coact with one bar being transverely aligned with the vertical unit which coacts with the other bar. 